In order to obtain high resolution structural information from proteins with electron crystallographic technique, one needs highly ordered two-dimensional crystals. The procedure that was pioneered by Roger Kornberg and colleagues to form two-dimensional periodic array onto a phospholipid monolayer appears to be a promising approach of preparing suitable two-dimensional crystals. Streptavidin has been made as two-dimensional periodic array on biotinylated lipid monolayer as described by Kubalek and co-workers. Our interest is aimed at examining as how high a structural resolution can be obtained with this type of two-dimensional crystal. The streptavidin crystal has a two-dimensional unit cell parameters of a=b= 82.3 _. They were preserved in vitreous ice and its electron diffraction pattern shows reflections beyond 3 _ resolution. High resolution electron images were acquired in the JEOL4000 electron cryomicroscope and the sum of Fourier transforms from multiple image areas showed detectable data also out to 3 _. Since the x-ray structure of streptavidin is known, it allows us to interpret our reconstruction map very readily. The projection map generated from electron diffraction amplitudes and phases from images shows detail at 3 _ where several of the beta strands of streptavidin are clearly resolved. In some high contrast regions of the map, they can be interpreted in terms of the side chains from either a monomer or a dimer. We also noticed that some regions of density between x-ray and electron crystallographic maps do not match well. This mismatch may be caused by conformational difference of the protein, the influence of the monolayer and/or experimental errors in the electron crystallographic technique. However, the dominant agreement of the density seen between two techniques provides a strong evidence that this type of monolayer crystal has the potential for high resolution electron crystallographic analysis.